US12102835B2 - Transmission unit comprising a transmission coil and a temperature sensor - Google Patents

Abstract

The invention relates to a transmitter unit (12) comprising a housing (20), a transmitter coil (18) arranged in the housing (20) for inductively transferring electrical energy to a receiver unit (14) which is provided with a receiver coil (16) and is arranged in the tissue (2) of the body (1) of a patient when the housing (20) having a contact surface (22) is placed on the body (1), and comprising a control device (30) for controlling the operation of the transmitter coil (18). According to the invention, a temperature sensor (26) is provided in the transmitter unit for determining a heating of the tissue (2) of the body (1) caused by the inductive transfer of electrical energy to the receiver unit (14). The invention also relates to methods for determining the temperature (T_Korr) of the tissue (2) of a body (1) on a surface (38), by which electrical energy is inductively transmitted for supplying an electrical consumer arranged in the tissue (2) of the body (1), and to a method for inductively transferring electrical energy.

Description

The invention relates to a transmitter unit comprising a housing, comprising a transmitter coil disposed in said housing for inductively transferring electrical energy to a receiver unit, which is disposed in a part of the body of a person, in particular a patient, e.g. in the tissue of a body of a patient, and comprises a receiver coil, when a contact surface of said housing is in contact with the body, and comprising a control device for controlling the operation of the transmitter coil.

The invention also relates to a method for determining the local temperature of a body of a person, in particular a patient, on a surface, e.g. the temperature of the tissue of the body on a surface, through which electrical energy for supplying an electrical consumer disposed in the tissue of the body is inductively transferred and to a method for inductively transferring electrical energy. The invention in particular relates to a method for determining the temperature on a surface in an apparatus for inductively transferring energy. The invention further relates to an apparatus which is operated according to a method according to the invention as well as the use of the method according to the invention.

In the medical field, methods for inductively transferring energy, in which an energy store in the form of a rechargeable battery disposed inside a body can be charged by inductive means, are already well-known in the state of the art (DE 10 2016 106 683 A1). For this purpose, a receiver coil disposed in a receiver unit inside the body of a patient cooperates with a transmitter coil disposed in a transmitter unit outside the body. Between the receiver coil and the transmitter coil, which are positioned at a defined, relatively small distance to one another, there is human tissue or the skin of the patient. During the operation of the transmitter coil, the tissue of the patient between the receiver unit and the transmitter unit is warmed, in particular as a result of thermal losses in the transmitter unit and in the receiver unit. The level of warming is limited for health reasons and may not exceed a certain amount.

The object of the invention is to enable the inductive transfer of electrical energy to a powerful electrical consumer or electrical energy store disposed, for example, in the body of a patient, without damaging the tissue of the patient.

This object is achieved by the transmitter unit specified inClaim1 and the methods specified inClaim18 and Claim20.

Advantageous embodiments of the invention are specified in the dependent claims.

The invention is based on the idea that monitoring the temperature of the surface of a patient in the region of direct contact with the transmitter unit makes it possible to infer information about the warming of the tissue of the patient.

One finding of the invention is that the measurement signals of a temperature sensor, which is disposed as close as possible to the to-be-measured surface, are affected by the inductive transfer of electrical energy. It is evident that, during operation of the transmitter coil, not only the (human) tissue or the skin surface of the patient is warmed, but that the magnetic fields produced by the transmitter coil also warm the temperature sensor or its leads, which results in a measurement error. Taking into account a not-to-be-exceeded (limit) temperature of the tissue in the transfer region of the apparatus, this then means that the operation of the transmitter coil is not optimized yet, or the registered temperature does not correspond to the actual temperature on the to-be-measured surface of the patient.

The invention has the advantage that it makes optimum use of the foreseen (allowable) maximum temperature increase of the tissue of the patient in the effective region of the transmitter unit or the transmitter coil, and thus makes it possible to optimize or maximize the transfer of energy into the receiver coil. This then enables short charging times for an electrical energy store, e.g. in the form of a rechargeable battery, disposed in the body of the patient, for example, or the possibility of reducing the time the externally disposed transmitter unit or transmitter coil is worn on the body.

One idea of the invention is that the component of the warming of the temperature sensor caused by the fields of the transmitter coil of the transmitter unit is taken into account when the temperature of the to-be-measured surface is registered. Taking into account the component of the warming of the temperature sensor caused by the (magnetic) fields emitted by the transmitter coil therefore reduces the temperature on the surface determined by the temperature sensor, which results in longer operating times, and/or makes it possible to set stronger magnetic fields of the transmitter coil, before a specific not-to-be-exceeded temperature limit value on the to-be-measured surface is actually reached.

In a variant of the method as described thus far, it can be provided that the component of the warming of the temperature sensor or its input leads is taken into account as a fixed value resulting from taking into account a given maximum operating time of the apparatus and given environmental parameters. This means that it has been determined, in particular on the basis of series of tests, by what amount of temperature the temperature sensor is warmed when it is exposed to a typical maximum operating time of the transmitter coil, taking into account a typical maximum outside temperature, for example. If this value is 0.8 Kelvin, for example, this maximum temperature increase of the temperature sensor (0.8 Kelvin) is subtracted from the respective value of the temperature on the surface currently registered by the temperature sensor, to thereby infer the actual maximum prevailing temperature on the surface.

In a further variant modified from the variant described above, an actually existing warming of the temperature sensor resulting from the operation of the transmitter coil can be taken into account by determining the component of the warming of the temperature sensor taking into account the registered temperature progression of the sensed surface after the operation of the transmitter coil of the apparatus has been stopped. This means that, after the operation of the transmitter coil of the apparatus is stopped, the temperature sensor continues to register the temperature on the to-be-measured surface and delivers it as input values to the control device of the apparatus. The actually existing temperature on the to-be-measured surface at the time the operation of the transmitter coil is stopped can be inferred using the temperature drop that occurs over time and is caused, on the one hand, by the no longer occurring transfer of heat into the human body and, on the other hand, by the heat dissipation from the temperature sensor.

In a further development of this method, it is provided that the operation of the transmitter coil is stopped periodically. The temperature on the to-be-measured surface of the patient can thus be monitored throughout the entire charging phase or the phase in which energy is transferred from the transmitter coil to the receiver coil.

There are a number of different ways to infer the actual temperature of the to-be-measured surface. In a first, particularly preferred method, the component of the warming of the temperature sensor caused by the operation of the transmitter coil is determined on the basis of a mathematical function taking into account known parameters of the temperature sensor and, if applicable, environmental parameters. Known parameters of the temperature sensor are in particular understood to be its heat storage capacity, its placement inside the housing of the transmitter unit, and thus its heat dissipation or cooling. Environmental parameters are in particular understood to be the external ambient temperature in the region of the transmitter unit and, if applicable, the current body temperature of the patient. The mentioned parameters of the temperature sensor and the apparatus or the housing of the apparatus and the ambient temperature can be brought into a mathematical relationship, for example using series of tests, such that, for example, a specific cooling function of the temperature sensor is established at a specific ambient temperature. This function can therefore be used to extrapolate or estimate the actual temperature on the to-be-measured surface at the time the transmitter coil is switched off.

In an alternative configuration of the method, however, it can also be provided that the temporal progression of the temperature registered by the temperature sensor after the transmitter coil is switched off is compared to curve progressions stored in the control device and, if it matches or approximates a stored curve progression, the actual temperature in the region of the to-be-measured surface at the time the transmitter coil is switched off can be inferred.

For a further optimization of the energy transfer to shorten charging times or to achieve the highest possible charging rates for the electrical energy store disposed in the patient, it is proposed that the apparatus for inductively transferring energy is controlled on the basis of the determined temperature, and that the transmitter coil is periodically not operated to avoid the occurrence of excessively high temperatures, wherein the duration of the operating breaks of the transmitter coil is based on the determined temperature on the surface. This means that the length of the operating breaks is selected to be such that they last only until the registered temperature is at a specific minimum separation from the limit value. The temperature on the to-be-measured surface is thus always kept just below the limit temperature, which overall enables an optimization of the energy transfer. Alternatively, it is also possible to throttle or adjust the transmission power to keep the temperature constant without operating breaks.

The invention also includes an apparatus for inductively transferring energy comprising a transmitter coil disposed in a housing, wherein the housing can be positioned at least in indirect contact with the to-be-measured surface, and wherein the apparatus is operated according to a method, in which the component of the warming of the temperature sensor is determined taking into account the registered temperature progression of the sensed surface after the operation of the transmitter coil of the apparatus is stopped. According to the invention, this apparatus comprises a temperature sensor, which can be exposed to the electromagnetic field of the transmitter coil so that said sensor is disposed in an operative connection with said coil. The apparatus can comprise an algorithm for determining the component of the warming of the temperature sensor or its input leads caused by the transmitter coil.

For the sake of making the apparatus as compact as possible, it is preferably provided that the temperature sensor is of an SMD design.

Lastly, the invention also includes the use of a method according to the invention as described thus far for determining the skin and/or tissue temperature in a human body during a transfer of energy into the human body, in particular with a VAD (ventricular assist device) system.

Further advantages, features and details of the invention emerge from the following description of preferred design examples. These are shown schematically in the drawings and are described below.

The figures show:

FIG.1 an apparatus for inductively transferring energy comprising a transmitter coil and comprising a temperature sensor, which is used for inductively transferring energy into a receiver unit having a receiver coil in a VAD system disposed in a human body;

FIG.2 a first diagram with the temporal progression of a temperature T registered by the temperature sensor in the apparatus for inductively transferring energy and with a limit temperature T_Grenz, and

FIG.3 a second diagram with the temporal progression of a temperature T registered by the temperature sensor in the apparatus for inductively transferring energy and with a limit temperature T_Grenz.

The same elements or elements having the same function are provided with the same reference signs in the figures.

FIG.1 shows the essential components of an apparatus10 for inductively transferring energy on areceiver unit14 disposed in thebody1 of a patient and having areceiver coil16 in a highly simplified manner. The apparatus10 is in particular a component of a cardiac support system in the form of a so-called ventricular assist device system (VAD system)100. The VAD system100 in particular includes a pump disposed in thebody1 of the patient, which supports the patient's heart function. In thebody1 of the patient, this pump is operated with electrical energy from an electrical energy store not shown inFIG.1, e.g. a rechargeable battery, which is connected to thereceiver unit14. This electrical energy store has to be charged due to the energy consumption of the pump. By inductively transferring energy into thereceiver unit14 by means of the apparatus10, the electrical energy store connected to thereceiver unit14 is charged.

The apparatus10 comprises atransmitter unit12 outside thebody1 of the patient and thereceiver unit14 with thereceiver coil16 disposed inside thebody1 of the patient. It should be noted that thereceiver unit14 may in principle comprise a plurality ofreceiver coils16.

Between thetransmitter unit12 and thereceiver unit14 there ishuman tissue2 or the skin of the patient. Thereceiver coil16 is disposed in operative connection with the electrical energy store to be charged. Thereceiver coil16 cooperates with atransmitter coil18 disposed in thetransmitter unit12. Thetransmitter coil18 is disposed inside a housing20 of thetransmitter unit12, whereby the housing20 is disposed at least in indirect contact with thebody1 or thetissue2 in the region of a contact surface22 of the housing20.

Thetransmitter coil18 has a coil winding17, which comprises conductor loops disposed around acoil axis19 that passes through the contact surface22. The coil winding17 of thetransmitter coil18 is located on atransmitter coil carrier21, which extends in a planar manner and through which thecoil axis19 passes, and which has a carrier surface that faces the contact surface22 of the housing20 for the coil turns of thetransmitter coil18.

To operate the apparatus10, it is also necessary for thereceiver coil16 and thetransmitter coil18 to be aligned with one another in order to be able to produce a magnetic field when current is supplied to thetransmitter coil18. The field lines24 of this magnetic field, which are shown inFIG.1, lead to the induction of an electrical voltage and thus to the flow of an electrical current in thereceiver coil16, which can then be used to charge the electrical energy store.

During operation of thetransmitter coil18, thetissue2 of thebody1 located between thetransmitter unit12 and thereceiver unit14 is warmed by the loss-related warming of thetransmitter unit12 and thereceiver unit14. This warming oftissue2 has to be limited to avoid physical impairments or damage and/or to comply with legal standards.

For this purpose, it is provided that the temperature of thetissue2 in the region of contact of the housing20 of thetransmitter unit12 with thetissue2 is monitored by means of atemperature sensor26 in the region of ameasurement surface38 on the surface of thetissue2.

Thetemperature sensor26 is disposed in the housing20 of thetransmitter unit12 on aside23 of thetransmitter coil18 facing the contact surface22.

To make the design as compact as possible, it is in particular provided that thetemperature sensor26 is designed as an SMD component or an SMD assembly. Thetemperature sensor26 is connected to acontrol device30 of thetransmitter unit12 via anelectrical lead28. Thecontrol device30 is also used to control thetransmitter coil18 via alead32. Afurther lead34 connects thecontrol device30 to afurther temperature sensor36, which is configured to register the ambient temperature outside thetransmitter unit12.

As can be seen inFIG.1, both thetemperature sensor26 and, if applicable, thelead28 are disposed in operative connection with themagnetic field lines24 of thetransmitter coil18. As a result, during operation of thetransmitter coil18, not only thetissue2 is warmed, in particular by the lost heat from thetransmitter unit12 and thereceiver unit14, but also thetemperature sensor26 or thelead28, in particular by the magnetic field of thetransmitter coil18, which can lead to thetemperature sensor26 heating up more than thesurrounding tissue2. This in turn has the consequence that the temperature increase of said components leads to a measurement error, which manifests itself in that the temperature T registered by thetemperature sensor26 in the region of themeasurement surface38 is falsified or increased by the measurement error.

To detect or take into account this measurement error or to register the actual temperature T on themeasurement surface38 of thebody1, thetransmitter coil18 is operated in a specific manner. For clarification, reference is made toFIG.2.

FIG.2 shows the temperature T registered by thetemperature sensor26 in the apparatus10 at the time t as a curve progression A. Thetemperature sensor26 transmits the temperature T registered at the time t to thecontrol device30.

The temperature T increases slightly in the period between t₀and t₁. The increase in temperature T can be explained by the fact that, during operation of thetransmitter coil18, both the temperature in thetissue2 and the temperature in thetemperature sensor26 or thelead28 is increased by the effect of the temporally changing magnetic field produced by thetransmitter coil18, which causes eddy currents. However, the temperature T is below a limit temperature T_Grenzthat has to be observed. At the time point t₁, the operation of thetransmitter coil18 is now stopped by thecontrol device30. The curve progression A then shows that the temperature T, which continues to be registered by thetemperature sensor26 and delivered to thecontrol device30 as an input quantity, decreases with thedecay curve40.

The curve progression A after the time point t₁results from both the now absent warming of thetissue2, or its cooling, and from the heat dissipation or cooling of thetemperature sensor26 and thelead28.

An algorithm with a mathematical function is stored in thecontrol device30 of thetransmitter unit12 or the apparatus10, which makes it possible to infer the actual temperature T in the region of themeasurement surface38 at the time point t₁based on the values of the temperature T after the time point t₁, for example by extrapolation from the cooling rate V_Kat a time point t₂after the time point t₁. This makes use of the fact that, due to its size, thetemperature sensor26 has a significantly lower heat storage capacity than thesurrounding tissue2 and the surface of the housing20. As a result, there is a dynamic drop in the temperature T immediately after thetransmitter coil18 is switched off at the time point t₁. Once this temporary equalization process is completed at the time point t₂, thetemperature sensor26 registers the actual temperature T of thetissue2, because the low heat storage capacity of thetemperature sensor26 has been “discharged”. The mentioned extrapolation of the cooling curve at the switch-off time t₁can therefore be used to infer the actual temperature at the switch-off time t₁. The additional warming of thetemperature sensor26 is thus taken into account or eliminated.

Alternatively, it can be provided that the curve progression A after the time point t₁is compared to curve progressions stored in thecontrol device30, and, if it matches or approximates a stored curve progression, the respective temperature T_Korrat themeasurement surface38 of thebody1 at the time point t₁is inferred. The difference between the corrected temperature T_Korron themeasurement surface38 and the temperature T registered at the time point t₁is the component ΔW caused by the warming of thetemperature sensor26 and thelead28.

As soon as the temperature T on themeasurement surface38, which has been corrected by the amount of warming of thetemperature sensor26 or thelead28 caused by the operation of thetransmitter coil18, has been determined, thecontrol device30 again actuates thetransmitter coil18 in order to enable a further transfer of energy. In order to enable continuous monitoring of the (actual) temperature T on themeasurement surface38, the switching off or switching on of thetransmitter coil18 as described thus far is preferably carried out periodically, i.e. at regular intervals.

FIG.3 shows a diagram that illustrates a simplified measurement procedure. Here, the temperature T registered by thetemperature sensor26 is again shown over the time t. A continuous, i.e. uninterrupted, operation of thetransmitter coil18 is assumed. The values of the temperature T transmitted by thetemperature sensor26 to thecontrol device30 are indicated by the curve progression A. The curve progression A_Kshows a corrected curve progression A taking into account a fixed value OF as the component ΔW, which is assumed to be the maximum possible measurement error resulting from the warming of thetemperature sensor26 and thelead28 due to the warming caused by the operation of thetransmitter coil18. In other words, this means that thecontrol device30 assumes that the temperature T calculated using the A_Kis the highest possible temperature that can be present on themeasurement surface38.

Of course, in both methods it is respectively assumed that the operation of the apparatus10 or thetransmitter coil18 is stopped when a limit temperature T_Grenzis approached, for example until the determined temperature T has a specific separation from the limit temperature T_Grenz.

The methods as described thus far can be altered or modified in a variety of ways without departing from the idea of the invention. It should in particular be noted that the described methods are not limited to use in a VAD system100.

In summary, the following preferred features of the invention should in particular be noted:

Atransmitter unit12 comprises a housing20 and atransmitter coil18 disposed in said housing20 for inductively transferring electrical energy to areceiver unit14, which is disposed in thetissue2 of thebody1 of a patient and comprises areceiver coil16, when a contact surface22 of said housing20 is in contact with thebody1. Thetransmitter unit12 comprises acontrol device30 for controlling the operation of thetransmitter coil18. The transmitter unit comprises atemperature sensor26 for determining a local warming of thebody1 caused by the inductive transfer of electrical energy into thereceiver unit14. The invention also relates to methods for determining the temperature (T_Korr) of abody1 on asurface38 through which electrical energy for supplying an electrical energy store or an electrical consumer disposed in thebody1 is inductively transferred and to a method for inductively transferring electrical energy.

The invention relates, in particular, to the aspects specified in the following clauses:

• • 1. Method for determining the temperature (T) on a surface (38) in apparatus (10) for inductively transferring energy, wherein the apparatus (10) comprises a transmitter coil (18) disposed in a housing (20) and the housing (20) is disposed at least in indirect contact with the to-be-measured surface (38), and comprising a temperature sensor (26) for registering the temperature (T) of the surface (38), wherein the temperature sensor (26) and, if applicable, the electrical lead (28) of said sensor is disposed in operative connection with the transmitter coil (18), such that, during operation of the transmitter coil (18), the temperature sensor (26) and, if applicable, the electrical lead (28) of said sensor is warmed by the fields emitted by the transmitter coil (18), so that the temperature (T) registered by the temperature sensor (26) includes a component (ΔW) that results from the warming of the temperature sensor (26) and, if applicable, the electrical lead (28) of said sensor by the transmitter coil (18), and wherein the component (ΔW) resulting from the transmitter coil (18) is taken into account in the registering of the temperature (T) of the measurement surface (38).
  • 2. Method according toclause 1, characterized in that that the component (ΔW) is taken into account as a fixed value (ΔF), which is obtained by taking into account a given maximum operating time of the apparatus (10) and given environmental parameters.
  • 3. Method according toclause 1, characterized in that the component (ΔW) of the warming is determined taking into account the registered temperature progression (A) of the sensed surface (38) after the operation of the transmitter coil (18) of the apparatus (10) is stopped.
  • 4. Method according to clause 3, characterized in that the operation of the transmitter coil (18) is stopped periodically.
  • 5. Method according to clause 3 or 4, characterized in that the component of the warming (ΔW) is determined on the basis of a mathematical function, taking into account known parameters of the temperature sensor (26), such as its heat storage capacity storage capacity, and, if applicable, environmental parameters.
  • 6. Method according to clause 3 or 4, characterized in that the component of the warming (ΔW) is based on a comparison of the temperature progression (A) on the sensed surface (38) with stored curve progressions.
  • 7. Method according to any one ofclauses 1 to 6, characterized in that the apparatus (10) for inductively transferring energy is controlled on the basis of the determined temperature (T) and the transmitter coil (18) is periodically not operated to avoid the occurrence of excessively high temperatures (T), wherein the duration of the operating breaks of the transmitter coil (18) is based on the determined temperature (T) on the surface (38).
  • 8. Apparatus (10) for inductively transferring energy, comprising a transmitter coil (18) disposed in a housing (20), wherein the housing (20) can be positioned at least in indirect contact with a to-be-measured surface (38), wherein the apparatus (10) is operated according to a method according to any one of Clauses 3 to 7, characterized in that a temperature sensor (26) is disposed in operative connection with the transmitter coil (18), and that the apparatus (10) comprises an algorithm for determining the component (ΔW) of a warming of the temperature sensor (26) and, if applicable, the lead (28) of said sensor caused by the fields emitted by the transmitter coil (18).
  • 9. Apparatus according to clause 8, characterized in that the temperature sensor (26) is of an SMD design.
  • 10. Use of the method according to any one ofclauses 1 to 7 for determining the skin and/or tissue temperature of a human body (1) during an energy transfer in the human body (1), in particular in a VAD system (100).

LIST OF REFERENCE SKINS

• • 1 Body
  • 2 Human tissue
  • 10 Apparatus
  • 12 Transmitter unit
  • 14 Receiver unit
  • 16 Receiver coil
  • 17 Coil winding
  • 18 Transmitter coil
  • 19 Coil axis
  • 20 Housing
  • 21 Transmitter coil carrier
  • 22 Contact surface
  • 23 Side
  • 24 Field line
  • 26 Temperature sensor
  • 28 Electrical lead
  • 30 Control device
  • 32 Lead
  • 34 Further lead
  • 36 Further temperature sensor
  • 38 Measurement surface
  • 40 Decay curve
  • 42 Section
  • 100 Ventricular assist device (VAD) system
  • A Curve progression
  • A_KCorrected curve progression
  • T Temperature
  • T_GrenzLimit temperature
  • T_KorrCorrected temperature
  • t Time
  • V_KCooling rate
  • ΔW Component
  • ΔF Fixed value

Claims (20)

The invention claimed is:

1. A transmitter unit comprising:

a transmitter coil configured to inductively transfer electrical energy to a receiver unit disposed in a living body;

a temperature sensor configured to determine an increase in local temperature of the living body caused by the inductive transfer of electrical energy to the receiver unit; and

a control device configured to control operation of the transmitter coil based at least in part on the increase in local temperature of the living body,

wherein the control device stores a temperature determination routine configured to determine a local temperature at a surface of the living body based at least in part on temperature measurement signals of the temperature sensor and accounting for warming of the temperature sensor caused by the transmitter coil.

2. The transmitter unit ofclaim 1 further comprising a housing, wherein the transmitter coil is disposed in the housing and the temperature sensor is positioned between the transmitter coil and a contact surface.

3. The transmitter unit ofclaim 1, wherein the temperature determination routine is configured to account for an operating state of the transmitter coil.

4. The transmitter unit ofclaim 1, wherein the temperature determination routine is configured to stop the operation of the transmitter coil at a first time point.

5. The transmitter unit ofclaim 1, wherein the warming of the temperature sensor is caused by eddy currents.

6. The transmitter unit ofclaim 5, wherein the temperature determination routine contains an algorithm, wherein the algorithm is configured to calculate the local temperature at the surface of the living body based at least in part on extrapolation of a decay curve from a second time point following a first time point to the first time point.

7. The transmitter unit ofclaim 6, wherein the algorithm is configured to calculate the local temperature at the surface of the living body based at least in part on extrapolation of a decay curve from a second time point following the first time point to the first time point.

8. The transmitter unit ofclaim 6, wherein the algorithm is configured to linearly extrapolate a progression of the decay curve from a second time point to the first time point.

9. The transmitter unit ofclaim 6, wherein the algorithm is configured to subtract a fixed correction value from temperature values corresponding to the temperature measurement signals.

10. The transmitter unit ofclaim 1, wherein the control device stores a shutdown routine configured to stop the operation of the transmitter coil, wherein the shutdown routine is configured to prevent or reduce the inductive transfer of electrical energy to the receiver unit when the local temperature determined by the temperature determination routine exceeds a threshold value.

11. A system comprising:

a temperature sensor;

a transmitter coil;

a memory storing computer-readable instructions; and

a processor configured to communicate with the temperature sensor, the transmitter coil, and the memory, wherein the computer-readable instructions, when executed, cause the processor to:

prevent an inductive transfer of electrical energy from the transmitter coil at a first time point;

determine a first temperature of a surface of a living body a second time point following the first time point;

and

calculate a local temperature of the surface of the living body based at least in part on temperature measurement signals of the temperature sensor and accounting for warming of the temperature sensor caused by the transmitter coil.

12. The system ofclaim 11 the computer-readable instructions further comprising:

determine a decay curve based at least in part on the first temperature measured at a second time point following the first time point.

13. The system ofclaim 12, wherein the calculation uses an algorithm, wherein the algorithm is configured to determine the local temperature of the surface of the living body at least in part by extrapolating a progression of a section of the decay curve from the second time point following the first time point to the first time point.

14. The system ofclaim 13, wherein the algorithm is configured to extrapolate the progression of the section of the decay curve based at least in part on a comparison of the decay curve with one or more decay curve progressions stored in the memory.

15. The system ofclaim 13, wherein the algorithm is configured to linearly extrapolate the progression of the decay curve from the second time point to the first time point.

16. The system ofclaim 12, wherein the preventing the inductive transfer of electrical energy from the transmitter coil at the first time point, the measuring the temperatures at the surface at a second time point following the first time point, the determining the decay curve from the temperatures measured at the first time point, and the calculating the local temperature at the surface of the living body based at least in part on the decay curve and an algorithm configured to account for an effect of inductive transfer of electrical energy from the transmitter coil to an electrically powered device are repeated continuously.

17. A method for determining a local temperature at a surface of a living body, wherein electrical energy for an electrical energy storage or an electrically powered device disposed in the living body is inductively transferred through the surface, the method comprising:

preventing an inductive transfer of the electrical energy at a first time point;

determining temperatures measured at the surface at a plurality of time points following the first time point;

and

calculating the local temperature at the surface based at least in part on temperature measurement signals of a temperature sensor and accounting for warming of the temperature sensor caused by a transmitter coil.

18. The method ofclaim 17 further comprising:

determine a decay curve based at least in part on the temperatures measured at a second time point of the plurality of time points following the first time point.

19. The method ofclaim 17, wherein the calculation uses an algorithm, wherein the algorithm is configured to determine the local temperature of the surface of the living body at least in part by extrapolating a progression of a section of a decay curve from a second time point of the plurality of time points following the first time point to the first time point.

20. The method ofclaim 19, wherein the algorithm is configured to extrapolate the progression of the section of the decay curve based at least in part on a comparison of the decay curve to one or more decay curve progressions stored in a data memory.

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